1. Field of the Invention
The present invention relates to an information processing apparatus, a control method of the information processing apparatus, and a program.
2. Description of the Related Art
If a conventional information processing apparatus sets its security level regarding data leakage high, data in a nonvolatile storage apparatus, for example, a hard disk drive (HDD) may be completely deleted after using the data. Japanese Patent Application Laid-Open No. 2004-005586 discusses a technique for completely deleting data in an HDD after using the data by overwriting the data in the HDD with other data.
However, if a method similar to the method for the HDD (method of overwriting a logical block addressing (LBA) to be deleted with data) is adopted as a data deletion method for a semiconductor storage apparatus, for example, a solid state drive (SSD), data inside the SSD cannot be completely deleted. The LBA is a method of specifying a sector with a serial number by assigning the serial number to all sectors in a hard disk.
However, if the same LBA is overwritten with other data by adopting the same method as that of the HDD for data deletion processing from the SSD, another physical address is assigned and written to the LBA due to a wear leveling operation, so that data will remain somewhere in the SSD.
The wear leveling operation is one method of increasing the life of a flash memory by writing in a distributed manner. More specifically, a semiconductor storage apparatus that performs wear leveling performs writing by rearranging blocks so that blocks that are less frequently written into are used if possible.
Thus, if the same data deletion method as that for the HDD is applied to such a semiconductor storage apparatus to overwrite the apparently the same LBA with other data, another physical address is actually specified due to block rearrangement control by ware leveling. Therefore, information may remain in a block before the rearrangement in the SSD.
Thus, if the security level (safety level) for data deletion is set high to delete data when job execution ends, data to be deleted may remain somewhere in a chip inside the SSD.
Therefore, there is an issue that even if the safety level set by the user is set high, data to be deleted actually remains in the SSD and requirements of data confidentiality cannot be met.